UV Radiation Injures Epidermal Keratinocytes
Placeholder: UV-B and UV-A penetrate skin and damage keratinocyte DNA and membranes.
- Epidermis: UV-B penetration (Placeholder short note)
- Dermis: UV-A penetration (Placeholder short note)
- CPDs: DNA lesion type (Placeholder short note)
- Minutes: Damage onset (Placeholder short note)
Mechanism of UV keratinocyte injury
Placeholder: UV photons induce direct DNA damage and oxidative stress in keratinocytes.
Apoptosis Exposes Nuclear Autoantigens
Placeholder: damaged keratinocytes undergo apoptosis, translocating antigens to cell surface blebs.
- Intrinsic: Apoptosis pathway (Placeholder short note)
- Ro/La, dsDNA: Key antigens (Placeholder short note)
- Impaired: Clearance defect (Placeholder short note)
- Surface: Bleb exposure (Placeholder short note)
Antigen translocation during apoptosis
Placeholder: nuclear antigens relocate to apoptotic blebs, becoming accessible.
Autoantibodies Recognize Exposed Antigens
Placeholder: circulating autoantibodies bind exposed antigens, forming immune complexes.
- IgG, IgM: Antibody classes (Placeholder short note)
- Rapid: Complex formation (Placeholder short note)
- Yes: Complement activation (Placeholder short note)
- Triggered: Local inflammation (Placeholder short note)
Immune complex formation at skin surface
Placeholder: antibody-antigen binding activates complement and recruits immune cells.
Inflammation Produces Visible Skin Lesions
Placeholder: immune complex deposition drives erythema and characteristic lupus lesions.
- Malar rash: Lesion type (Placeholder short note)
- Hours–days: Onset window (Placeholder short note)
- Interface dermatitis: Histology (Placeholder short note)
- Face, chest: Common sites (Placeholder short note)
From immune complex to visible rash
Placeholder: local inflammatory cascade manifests as cutaneous lupus lesions.
Cutaneous Injury Provokes Systemic Flare
Placeholder: skin-derived inflammatory signals can trigger systemic disease activity.
- Joints, kidney: Flare organs (Placeholder short note)
- IFN-alpha: Cytokine surge (Placeholder short note)
- Sun protection: Risk modifier (Placeholder short note)
- SPF50+: Prevention (Placeholder short note)
Systemic amplification of cutaneous injury
Placeholder: cytokines from skin injury circulate and provoke systemic flare.
Placeholder: consistent photoprotection substantially reduces flare risk.